For more than a century, paleoanthropologists have been at loggerheads over the origin of modern humans. Two factions occupy the forefront of the debate: those who subscribe to the Out of Africa theory, which holds that Homo sapiens arose in Africa alone between 200,000 and 150,000 years ago and subsequently spread across the globe, replacing archaic hominids; and those who espouse the multiregional evolution theory, which proposes that modern humans emerged from archaic populations across the Old World.
The Out of Africa model has come out as the clear favorite, bolstered by numerous genetic studies. Critics, however, have charged that fossil support for the theory is flimsy. If Africa was the fountainhead of modern human morphology, then the first modern-looking fossils should come from that continent. But a hole in the African fossil record between 300,000 and 100,000 years ago, when the transition to morphological modernity is believed to have occurred, has prevented scientists from testing that prediction.
This article was originally published with the title Sourcing Sapiens.